What does the Emergency Power System (EPS) primarily provide in the event of a failure?

The Emergency Power System (EPS) is designed to provide critical power in the event of a battery bus failure. This is essential for maintaining vital systems and ensuring the safety and operability of the aircraft in emergency situations. The EPS is specifically engineered to activate when the primary power source fails, allowing for the continued operation of key systems that are necessary for safe flight and effective emergency procedures.

While the other choices may suggest important functions within the aircraft, they do not reflect the primary purpose of the EPS. For instance, while the lighting system and cabin climate control are important for passenger comfort and safety, they may not be the first priority in an emergency scenario where flight control and navigational systems must remain operable. Additionally, providing power solely to avionics would not encompass the comprehensive role of the EPS, which is focused on ensuring that multiple vital systems can still function at critical moments during a flight. Thus, the EPS is a crucial component for maintaining operational integrity and pilot awareness when the primary power systems are compromised.